[dif-uh-ren-shee-ey-ter] 
| 1. | a person or thing that differentiates. |
| 2. | Computers. an electronic device whose output signal is proportional to the derivative of its input signal. |
| 3. | Electricity, Electronics. a transducer or circuit (differentiator circuit) whose output is proportional to the rate of change of the input signal. |
differentiator
a device or set of components for performing the mathematical operation of differentiation-i.e., supplying an output proportional to the derivative of the input with respect to one or more variables. The many common examples of mechanical differentiators in which a displacement is differentiated with respect to time include speedometers and generators. In such devices, the derivative is frequently measured by deflections of spring-loaded elements
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əˈrɛn